Browsing by Author "Moloney, Padraig G."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Low electrical resistivity carbon nanotube and polyethylene nanocomposites for aerospace and energy exploration applications
    (2012) Moloney, Padraig G.; Barrera, Enrique V.
    An investigation was conducted towards the development and optimization of low electrical resistivity carbon nanotube (CNT) and thermoplastic composites as potential materials for future wire and cable applications in aerospace and energy exploration. Fundamental properties of the polymer, medium density polyethylene (MDPE), such as crystallinity were studied and improved for composite use. A parallel effort was undertaken on a broad selection of CNT, including single wall, double wall and multi wall carbon nanotubes, and included research of material aspects relevant to composite application and low resistivity such as purity, diameter and chirality. With an emphasis on scalability, manufacturing and purification methods were developed, and a solvent-based composite fabrication method was optimized. CNT MDPE composites were characterized via thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Raman spectroscopy, and multiple routes of electron microscopy. Techniques including annealing and pressure treatments were used to further improve the composites' resulting electrical performance. Enhancement of conductivity was explored via exposure to a focused microwave beam. A novel doping method was developed using antimony pentafluoride (SbF 5 ) to reduce the resistivity of the bulk CNT. Flexible composites, malleable under heat and pressure, were produced with exceptional electrical resistivities reaching as low as 2*10 -6 Ω·m (5*10 5 S/m). A unique gas sensor application utilizing the unique electrical resistivities of the produced CNT-MDPE composites was developed. The materials proved suitable as a low weight and low energy sensing material for dimethyl methylphosphonate (DMMP), a nerve gas simulant.
  • Thumbnail Image
    Item
    NASA's Relationship with Nanotechnology: Past, Present, and Future Challenges
    (James A. Baker III Institute for Public Policy, 2012) Matthews, Kirstin R.W.; Carey, Brent J.; Evans, Kenneth M.; Moloney, Padraig G.; Baker Institute Science and Technology Policy Program
    This report reviews the history of nanotechnology research and development at NASA over the past 15 years. Nanotechnology is used to illustrate how NASA has guided new technology development at its own research facilities and through collaborations with university scientists and laboratories. We demonstrate that nanotechnology is representative of NASA's long struggle to translate research projects into viable technologies.